# Comparative Analysis of Submaximal and Maximal Effort Capacities in Patients Post-COVID-19 and Individuals with Chronic Restrictive Lung Diseases

## TL;DR

This study compares lung function and effort capacity in post-COVID-19 patients and those with chronic restrictive lung diseases.

## Contribution

The study identifies similarities in submaximal and maximal effort capacities between post-COVID-19 and chronic restrictive lung disease patients.

## Key findings

- Post-COVID-19 and chronic RLD patients showed similar patterns in spirometry, 6-MWT, and CPET variables.
- Forced vital capacity correlated with 6-MWT distance and speed, and inversely with maximal minute ventilation.
- The degree of lung restriction affected performance in submaximal and maximal effort tests.

## Abstract

Whether impairments in submaximal and maximal effort capacities in individuals following acute COVID-19 infection resemble those found in patients with chronic pulmonary disease remains unclear. We aimed to analyze the submaximal and maximal effort capacities of patients after COVID-19 infection and those with alterations in lung mechanics similar to those observed in patients with chronic respiratory diseases. This retrospective cross-sectional observational study paired a group of post-COVID-19 individuals with another group of patients with chronic respiratory disease, using spirometric patterns similar to those observed post-COVID-19. Data from Spirometry, 6 min walk test (6-MWT), and cardiopulmonary exercise test (CPET) variables were compared, and correlations between spirometric variables and 6-WT/CPET were examined. The final sample comprised 20 patients, including 10 post-COVID-19 patients with a restrictive lung disease (RLD) pattern identified using spirometry and 10 patients with RLD. Both groups presented similar patterns of the analyzed variables, with significant correlations observed between forced vital capacity (FVC) the distance and speed achieved during the 6-MWT, and a negative correlation between FVC and V’ E max. The degree of restriction in the overall sample influenced the covered distance and speed during the 6-MWT as well as the maximum minute ventilation during maximal effort.